Electronic manufacturing of printed circuit boards and the assembly of components onto boards use tin lead solders to provide a mechanical and electrical connection. Tin-lead solders yield highly reliable connections in automated soldering and manual soldering and provide a very solderable surface on printed circuit boards.
There are four specific areas of use for this solder.
1. Coating of circuit boards is accomplished in printed circuit board manufacture by "hot-air leveling" or "roll-tinning". This process improves solderability on the circuit board.
2. Assembly of electronic components on printed circuit boards is accomplished by use of these same tin lead alloys in a wavesoldering machine.
3. Assembly of electronic components using solder wire and a heating device to hand solder the components to the board.
4. Assembly of electronic surface mount components on printed circuit boards is accomplished by use of these same tin lead alloys in automated heating devices.
The alloy composition of the present invention has a melting temperature of 210.degree.-215.degree. C.
The use of tin-lead solders for this purpose is becoming more of a problem because of the toxic effects of lead exposure to workers and the generation of hazardous waste. In addition moves are afoot to limit the amount of lead going into our environment.
Because of the above there is a need to have a solder with no toxic elements that have physical characteristics and similar application performance as tin lead when applied as in sections 1, 2, & 3.